Young — Vcqiour-Pressiires, ^p., of Thirty Pure Suhstances. 387 



from Kalhbaum, the other was prepared from the alcohol and either the acid 

 or the anhydride by the usual methods. After removal of any free acid by 

 treatment with potassium carbonate, the ester was treated repeatedly with 

 phosphoric anhydride until, after standing all niglit, the liquid had the 

 appearance of a thin jelly. This appearance was never noticed until the 

 whole of the water and free alcohol had been removed by the phosphoric 

 anhydride. If necessary, the ester was distilled two or three times during 

 the treatment with the anhydride. It was then fractionated until a product 

 of constant boiling-point was obtained. The esters were always re-distilled 

 over phosphoric anhydride immediately before use. 



The following determinations of specific gravity were made at later dates 

 with fresh specimens, and in several cases with a different specific-gravity 

 tube. 



Methyl acetate, 0-95937. (Boiling-point, 57-1°.) 



Ethyl acetate, 0-92438, 0-92437, 0-92446. 



Propyl acetate, 0-91008. 



Ethyl propionate, 0-91251. 



